Lecithin product and process



Patented Aug. 17, 1937 UNITED STATES LECITHIN rnonocr AND raocass AlbertA. Lund, Port Washington, N. Y.

No Drawing.

22 Claims.

The present application is a continuation in part of my co-pendingapplication, Serial No. 39,- 997, flied September 10, 1935, which is inturn a continuation in part of my co-pending applicatlon, Serial No.750,396, filed October 27, 1934 now abandoned.

. This invention relates to fluid hydrates of lecithin, and/or relatedphosphatides, and includes processes for preparing the same.

Lecithin as now commercially available, consists of an emulsion ormixture of phosphatides and fat or saturated solutions of thesephosphatides in a parent vehicle, such as soya bean oil. Lecithin insuch mixtures is unstable, and

uniform and dependable results from use of these mixtures are difllcultto attain. Lecithin in this form is unsplit and is insoluble in aqueousmediums. The oil or fat protecting menstruum further interferes withmany other inherent 2o characteristics and properties of the colloid.The

present lecithin mixtures also contain decomposition products, such asoxidation and cleavage products ofthe oil and of the lecithin itself,which products further interfere with efllcient use of the substance.

I have discovered a new physical state of vegetable lecithin whereinrelatively high concentration of this substance may be obtained in acondition of true hydration. Lecithin in this condition avoidsdisadvantages attending prior art forms thereof for certain usesandpermits many new uses of the substance not heretofore feasible.

The hydrated lecithin of my invention is of uniform composition andhighly stable in form.

It is readily diffusible with either oil or water or complex mixturesthereof, and enters immediately into colloidal solution in aqueousmenstruums. Because of its great effect on surface 40 tension (lecithinin the form of this hydrate exhibits the maximum effect) it is capableof intimately and thoroughly wetting finely divided solids, as powders,closely woven textiles, and

the like. This novel lecithin product is further substantially devoid ofoils and fats and decomposition products resulting from oxidation,

cleavage, or the like.

According to this invention, the lecithin hydrate maybe isolated orprovided with a vehicle of water alone or water and a minor proportionof alcohol. Under the conditions of the process, there is no evidencethat the water exercises a hydrolyzing action on the lecithin; on thecontrary, the resulting hydrated lecithin has Application November 10,1936, Serial No. 110,183

a higher degree of protection against changes in composition than in theprior art oil phase.

My method of producing lecithin in the novel form above describedconsists generally in providlng a mixture of water, alcohol and a richundecomposed oieaginous phosphatide mixture, such as the type known asto 68% commercial lecithin in proportions lying approximately within thefollowing ranges:

Commercialvegetable lecithin, 15 to 25%; alcohol, 8 to 25%; water 58 to78%. The. water and alcohol are preferably heated to in the neighborhoodof F. and the lecithin then added, followed by agitation. When ahomogeneous mixture is obtained, it is allowed to come to naturalequilibrium at substantially normal temperature. The desired equilibriumwill be evidenced by the formation of the liquid mixture into threedistinct layers of three liquid phases in equilibrium, essentially:--(l)excess oil saturated with lecithin and alcohol and water; (2) excessalcohol and water saturated with lecithin and oil, and (3) lecithinsaturated with alcohol, water and oil.

The uppermost layer, or first phase, ordinarily comprises about 2%% to5% of the total mixture and possesses useful properties as anemulsifying oil and is a valuable by-product of the process. Theintermediate layer, or second phase, comprises usually about 24% to 28%of the mixture and may be re-used in the process either in place of, orin addition to the necessary water and alcohol. The bottom fraction, orthird phase, contains the lecithin hydrate herein -referred to and is atransparent reddish brown fluid of moderate viscosity. This fractioncomprises the bulk of the mixture and contains in a high state ofefiiciency about three-fourths of the commercial lecithin originallyintroduced into the mixture.

The above described lecithin hydrate containing traction may be used, ifdesired, without further treatment. The purity of the product, however,may be increased by subjecting the same to evaporation, preferably atreduced pressure, to evaporate oil the alcohol and a portion of thewater. Evaporation or purification may be carried to the point where theresulting product consists of alcohol-free hydrates substantially freeof unbound moisture and may be described as lecithin hydrate having avehicle of water. Experiments have shown that the efficiency of theunpurifled hydrate containing fraction or alcoholic hydrate is ten timesgreater than the ordinary stabilized lecithin emulsions and the emusedWith good results.

' mal temperature.

cie-ncy of the purified or alcohol-free hydrate is twenty times greater,varying to some extent, of course, depending upon the composition of theproduct in which the colloid is used.

The lecithin hydrate may, if desired, be isolated from its vehicle ofwater in a simple manner such as the following: The presence ofsalt-electrolytes in the water dispersed product keeps the phosphatidein the soluble form by peptization. Diminishing the amount of the saltspresent on neutralizing their charge bythe introduction of hydrogenions, such as addition of phosphoric acid, shrinks the volume of thelecithin containing phase by separating out the excess water. As thelowering of the pH is continued, the phosphatide is brought within ajellying range and in this state the product is a true hydrate oflecithin or hydrate of lecithinand itsCassociated phosphatides in thatall of the water is-in the bound condition and there is no free moisturev remaining. a

The lecithin hydrate of the present invention as a gel may besusceptible to synersis. This tendency may be reduced in any well knownmanner, suchas by employing sugar as a dehydrating agent in a 'mannersimilar to its use in Lpectin jellies, and thus it is possibleto'produce asolid lecithin or phosphatide hydrate jelly.'- The sugarfurther functions to act as a preservative in the recovered lecithinhydrate.

-Because of variations in the composition of commercial vegetablelecithins, itmay be found necessary in practice of the present process,to

add small critical'amounts of certain salts, and also small criticalamounts of acid to adjust the hydrogenion concentration of e thecommercial vegetable lecithin mixture to a point at which separationwill occur. 'Many salts may be used with varying efiiciencies; thosewith monovalent "cations and'organic negative radicals being preferredas sodium acetate or' sodium lactate. Many acids are suitable for use,but those too weakly acidic require large concentrations, relatively,while the strong ones are extremely critical as to concentration.Phosphoric acidmay be In cases where the addition of salt or acid, orboth, is found necessary, either or both of these reagents are added inamounts varying up toan additional 2% of the 7 original mixture.

'The water and alcohol are preferably heated to in the neighborhood ofF., the lecithin then added,-and then the salt or acid or both added,followed by agitation. When -a-"homogeneous mixture is obtained, it isallowed to come to natural equilibrium at substantially nor- The desiredequilibrium will be evidenced by the formation of the liquidmixture intothe distinct layers described previously.

In those cases 'where the addition 'of salt is necessary, the functionof the salt is to furnish positively chargedion's which will neutralizethe charges upon the negatively charged colloidal lecithin particles.The neutralized particles may then, by the absorption of water, swelland coalesce to form the desired hydrate. The hydrogen ion in the acidwill also perform this function, but the resulting lecithin-hydrate isnot'as satisfactoryfor many applications. The purpose in adding the acidis to'increase the emciency of the salt-electrolyte by the criticaladjustment of the hydrogen-ion concentration. A pH range of between 4.0and 6.0 is necessary to obtain the useful properties in the finalproduct, and preferably a range of between 4.5 and 6.0 should bemaintained. Lowering the pH by the addition of acid lowers the amount ofelectrolyte which must be added, but excessive lowering much below 4.5,materially lowers the efllciency of the desired product.

The theory of action of the process of this invention is believed to beas follows:

The process at the beginning involves a. four component system; .water,alcohol, lecithin and oil. After the period oforiginal mixing, these areall intimately and finely dispersed, and the lecithin saturated with oilor fat and fat saturated with lecithin.

Alcohol, in its critical minor proportion in water, first acts as asolvent, dissolving the fat and oil, leaving the lecithin in intimatecontact with water. Lecithin is slightly soluble in both water andalcohol and these two solvents are probably nearly saturated withlecithin at this point. I The remaining major portion of the lecithinremains in colloidal suspension in the wateralcohol solution. Thiscolloidal suspension is peptized by the alcohol. The lecithin particlesare negatively charged.

The lecithin in solution in the alcohol is in condition to becomehydrated, and 'water dissolves in it causing the particles to swell.After this has happened, another increment of the lecithin dissolves inthe alcohol, andthe hydration process continues until all of thelecithin is hydrated. In this instance, the alcohol is functioning as acatalyst.

As previously stated, the lecithin particles are negatively charged. Inthose cases in which it is found necessary to add electrolytes to inducethe system to separate into its final phases, the suspended particles oflecithin repell each other, and so are not able to assume their desiredrole as the external phase of the system lecithinwater; By the additionof critical amounts of positive ions, the neutralization of'the chargeson the lecithin in suspension is brought about. The lecithin particles'are then' enabled to swell" by the absorption of water,and lesseramounts of oil and alcohol until they coalesce. The excess water andalcohol present being squeezed out from the gel.

Adjustment of the hydrogen-ion concentration is not necessary, but ithas been found that it will speed up the above'reactions, and increasethe 'efiiciency of the electrolyter Although all alcohols and hydroxylcompounds and related solvents that are miscible with water are suitablein various degrees in the above described process, I prefer to usecommercial ethyl alcohol, or ethyl alcohol denatured with methyl alcoholbecause of their general acceptability in the food and beverage arts andindustrial arts respectively. Iso-propyl alcohol is also particularlydesirable as a.- lesser amount is required and evaporation isdiminished. Anhydrous lecithinis equally as applicable in the foregoingprocess instead of the commercial" lecithin recited,'andappropriate-minor adjustments in the proportions herein given may bemade as found advisable. It is also possible to use crude phosphatidecontaining materials such as soya bean residues as the starting materialinstead of manufactured soya-lecithin.

Instead of allowing themixture to spontaneously cool to normaltemperature prior to effecting separation, it is often desirable,particularly in large batch commercial practice, to accelerate coolingbyartificial means after the reaction is completed and then separate thecooled mixture material, and permitting'reaction in the mixture gravitysettling or 6. A process for producing lecithin. hydrate which comprisesproviding a homogeneous mixture of water, alcohol and phosphatidcontaining to form lecithin hydrate.

'7. A process for producing lecithin hydrate which comprises providing ahomogeneous mixture of water, alcohol, phosphatid containing material,and a sugar dehydrating agent, and permitting reaction in the mixture toform lecithin hydrate.

8. A process for producing lecithin hydrate which comprises providing ahomogeneous mixture of water, alcohol and phosphatid containingmaterial, permitting reaction in the mixture to form a fraction composedof lecithin hydrate, water and alcohol, and separating the alcohol fromsaid fraction.

9. A process/for producing lecithin hydrate having a vehicle of waterwhich comprises providing a homogeneous mixture of water. alcohol andcommercial lecithin, permitting reaction in the mixture to form afraction containing lecithin hydrate, water and alcohol, and separatingthe alcohol from said fraction.

10. A process for producing lecithin hydrate which comprises providing ahomogeneous mixture of water, alqohol and commercial lecithin, andpermitting spontaneous reaction in the mixture at normal temperatures toform lecithin hydrate.

11. A process of producing lecithin hydrate which comprises providing ahomogeneous mixture of water, alcohol and commercial lecithin,

permitting reaction inthe mixture at normal temperatures to formsuccessive layers containing lecithin hydrate, excess water and alcohol,and excess oil, and separately recovering said layers.

12. A process for producing lecithin hydrate which comprises providing ahomogeneous mixture consisting of water 58% to alcohol 8% to 25% andcommercial lecithin 15% to 25%, and permitting reaction in the mixtureat normal temperatures to form lecithin hydrate.

13. A process for producing lecithin hydrate which comprises separatinga substantial proportion of lecithin from a commercial lecithin oilmixture by solvent extraction, and reacting the separated lecithin withwater to form lecithin hydrate.

14. A process for producing lecithin hydrate which comprises separatinga substantial proportion of lecithin from a commercial lecithin oilmixture by solvent extraction, and reacting the separated lecithin withwater in the presence of an alcohol to form lecithin hydrate.

15. A process for producing lecithin hydrate which comprises separatinga substantial proportion of lecithin from a commercial lecithin oilmixture by solvent extraction with water and alcohol, and reacting theseparated lecithin with said water in the presence of said alcohol toform lecithin hydrate.

16. A process for producing lecithin hydrate which comprises providing ahomogeneous mixture consisting of water 58% to 75%, alcohol 8% to 25%.commercial lecithin 15% to 25% and an -agent capable of neutralizingnegatively charged lecithin, and permitting reaction in the mixture atnormal temperatures to form lecithin hydrate.

17. A process for producing lecithin hydrate which comprises separatinga substantial proportion of lecithin from a commercial lecithin oilmixture by solvent extraction, and reacting the separated lecithin withwater in the presence of an alcohol and cations capable of neutralizingnegatively charged lecithin to form lecithin hydrate.

18. The process for producing lecithin hydrate which comprisesseparating a substantial proportion of lecithin from a commerciallecithin oil mixture by solvent extraction with water and alcohol,reacting the separated lecithin with said water in the presence of saidalcohol and cations capable of neutralizing negatively charged lecithinto form lecithin hydrate.

19. A process for producing lecithin hydrate which comprises providing ahomogeneous mixture of water, alcohol, commercial lecithin, and an acidcapable of lowering the hydrogen ion concentration and permittingspontaneous reaction in the mixture at normal temperatures to formlecithin hydrate.

20. A process for producing lecithin hydrate which comprises providing ahomogeneous mixture of water, alcohol, commercial lecithin, and a saltcapable of neutralizing negatively charged lecithin, and permittingspontaneous reaction in the mixture at normal temperatures to formlecithin hydrate.

21. A process for producing lecithin hydrate which comprises providing ahomogeneous mixture of water, alcohol, commercial lecithin, a saltcapable of neutralizing negatively charged lecithin, and an acid capableof lowering the hydrogen ion concentration, and permitting spontaneousreaction in the mixture at normal temperatures to form lecithin hydrate.

22. A process for producing lecithin hydrate which comprises providing ahomogeneous mixture of water, alcohol and commercial lecithin, adjustingthe hydrogen ion concentration to a pH value of between 4.0-6.0, andequilibrating the mixture by the addition of an electrolyte to formlecithin hydrate.

ALBERT A. LUND.

